JP6195982B2 - Optical glass and optical element - Google Patents

Description

The present invention relates to an optical glass, and in particular, an optical glass having a refractive index (n _d ) of 1.60 to 1.65 and an Abbe number (ν _d ) of 62 to 66, and a glass preform and an optical element composed of the optical glass. And optical equipment.

  In recent years, with the improvement of image quality and high resolution development of digital cameras, digital video cameras, camera phones, etc., aspherical lenses have been widely handled, so glass with medium refractive index, low chromatic dispersion, and high transmittance. Are increasingly market oriented. At the same time, precision compression molding technology has become the first choice of optical glass optical lens manufacturing to reduce processing difficulty and manufacturing cost, but in order to make the obtained optical glass suitable for precision compression molding, The requirement for optical glass developers has become increasingly sophisticated because of the low transition temperatures required.

  The Chinese patent of application number 20101055454492 discloses optical glass, which has a glass transition temperature (GTT) of about 600 ° C. and is not suitable for precision compression molding.

Since the optical glass described in Japanese Patent Application Laid-Open No. 2004-217513 contains a relatively large amount of Nb ₂ O ₅ , Bi ₂ O ₃ , and WO ₃ , there is a problem of low transmittance.

The Chinese patent of application number 201010299001.2 discloses optical glass, which contains a large amount of B ₂ O ₃ , which increases the volatility when the glass melts and at the same time the chemical stability of the glass And devitrification resistance is insufficient.

  The problems to be solved by the present invention include a low transition temperature, high transmittance, good chemical stability and resistance to devitrification, a refractive index of 1.60 to 1.65, and an Abbe number of 62 to 66. It is to provide an optical glass.

In order to solve the above problems, the present invention provides an optical glass containing, in weight percentage, the following components:
30-50% of the _P 2 _O 5, _35~50% of BaO, 2 to 6 percent of _B 2 _O 3, _0~5% of _La 2 _O 3, _0~5% of _Gd 2 _O 3, 0.1 5% of _Al 2 _O 3, _0.1~5% of _Li 2 O, 2-10% of MgO, and 2-10% of CaO.

Additionally, the optical glass further contains 0-3% ZnO, 0-8% SrO, 0-0.5% Sb ₂ O ₃ .

Additionally, the components of the optical glass in weight percent, 30-50% of the _P 2 _O 5, 35 to 50 percent of BaO, 0 to 5% of the _La 2 _O 3, 0 to 5 percent of _Gd 2 _{O 3} 2-6% B ₂ O ₃ , 0.1-5% Al ₂ O ₃ , 0.1-5% Li ₂ O, 2-10% MgO, 2-10% CaO, 0 3% ZnO, a _Sb 2 _{O 3} 0-8% SrO and 0 to 0.5%.

In addition, the content of P ₂ O ₅ is 38-42%.

  In addition, the content of BaO is 39-45%.

In addition, the content of B ₂ O ₃ is 2.5-4.5%.

In addition, the content of Al ₂ O ₃ is 1-5%

In addition, the content of Li ₂ O is 1 to 3%.

  In addition, the content of MgO is 4-8%.

  In addition, the CaO content is 4-8%.

In addition, the content of Gd ₂ O ₃ is 0 to 3% and / or the content of La ₂ O ₃ is 0 to 3%.

In addition, BaO / (P ₂ O ₅ + B ₂ O ₃ ) is 0.9 or more and 1.5 or less.

In addition, La ₂ O ₃ + Gd ₂ O ₃ is 0.1% or more and 8% or less.

  Additionally, the optical glass has a refractive index of 1.60 to 1.65 and an Abbe number of 62 to 66.

In addition, when the transmittance of the optical glass reaches 80%, the corresponding wavelength is less than 370 nm, the optical glass (powder method) has a water resistance D _W of 1 and acid resistance D _A of 4 and is weather resistant. The nature is class 1 and the transition temperature does not exceed 550 ° C.

  A glass preform produced from the above optical glass.

  An optical element manufactured from the optical glass.

  An optical device manufactured from the optical glass.

The optical glass provided by the present invention has the following advantages. That is, P ₂ O ₅ is used as a glass network-forming substance, imparts high transmittance to the glass, and a large amount of BaO is an important component that improves the transmittance while improving the refractive index and weather resistance of the glass. By appropriately adjusting the content range of each component, an optical glass having a high transmittance, a low transition temperature, and a good chemical stability and devitrification resistance can be obtained. The refractive index is 1.60 to 1.65, and the Abbe number is 62 to 66. When the transmittance of the optical glass reaches 80%, the corresponding wavelength is less than 370 nm, the water resistance _DW of the optical glass is class 1, the acid resistance D _A is class 4, the weather resistance is class 1, the transition temperature Is suitable for precision compression molding of optical elements such as aspherical lenses, spherical lenses, and optical gratings.

  Each component of the optical glass of the present invention will be described as follows, but unless otherwise specified, the content of each component is expressed in wt%.

P ₂ O ₅ is a network-generating material, and as an important element for forming a glass framework, if its content is too small, devitrification resistance is deteriorated. When the content is excessive, the chemical stability is lowered, and further, the expected optical performance is hardly obtained. Therefore, the content of P ₂ O ₅ is limited to 30 to 50%, and preferably 38 to 42%.

B ₂ O ₃ is an essential component for high refractive index and low color dispersion. However, when the content of B ₂ O ₃ is large, the chemical stability and devitrification resistance of the glass are lowered. Therefore, the content of B ₂ O ₃ is limited to 2 to 6%, and a more preferable content is 2.5 to 4.5%.

  BaO is an essential component that improves the transmittance of glass and improves the refractive index and weather resistance. However, when the content is low, the required optical constant and excellent weather resistance cannot be achieved. On the other hand, when the content is excessive, the transition temperature rises and the chemical stability of the glass deteriorates. Therefore, the content of BaO is limited to 35 to 50%, and preferably 39 to 45%.

BaO is an important component for improving the transmittance of glass in a medium refractive index, low color dispersion glass. As a result of the inventors' devotion to research in order to obtain higher transmittance, it was found that there is a certain proportion between BaO and P ₂ O ₅ and B ₂ O ₃ . If BaO / (P ₂ O ₅ + B ₂ O ₃ ) is less than 0.9, the requirements for moderate refractive index and low color dispersion cannot be achieved even if the transmittance of the glass is high. However, when BaO / (P ₂ O ₅ + B ₂ O ₃ ) exceeds 1.5, BaO present in a large amount in the glass destroys the internal structure of the glass and the transmittance is deteriorated. Therefore, when BaO / (P ₂ O ₅ + B ₂ O ₃ ) is 0.9 to 1.5, a medium refractive index, low color dispersion, and high transmittance can be satisfied.

La ₂ O ₃ can increase the refractive index of the glass and improve the chemical stability and durability, but if its content is excessive, the transition temperature rises and the devitrification becomes worse. Therefore, the content is limited to 0 to 5%, and a more preferable content is 0 to 3%.

Gd ₂ O ₃ is an effective component that improves the refractive index and devitrification resistance of glass. However, when the content exceeds 5%, the transition temperature is improved and the devitrification resistance is deteriorated. Therefore, the content is limited to 0 to 5%, and a more preferable content is 0 to 3%.

When Gd ₂ O ₃ is an essential component of glass, La ₂ O ₃ can be a free additive component. When La ₂ O ₃ is an essential component of glass, Gd ₂ O ₃ can be a free additive component. However, when La ₂ O ₃ and Gd ₂ O ₃ are present in the glass at the same time, the total weight of both is ₂ to 8% of La ₂ O ₃ + Gd ₂ O ₃ . Otherwise, the glass transition temperature increases and the devitrification resistance deteriorates.

It is an important component that improves the chemical stability of Al ₂ O ₃ glass. However, when the content is 5% or more, the glass is difficult to melt and the transmittance is lowered, so the content of Al ₂ O ₃ is limited to 0.1 to 5%.

Li ₂ O is a necessary component of the present invention, and not only serves to remarkably lower the glass transition temperature and density, but also has a relatively strong flux action. However, when the content is lower than 0.1%, the role of lowering the transition temperature is not clear. When the content is higher than 5%, devitrification resistance and chemical stability are drastically lowered. Therefore, the content of Li ₂ O is 0.1 to 5%, and a more preferable content is 1 to 3%. The glass of the present invention contains only Li ₂ O and does not contain Na ₂ O and K ₂ O. Since Li ⁺ of smaller radius than the radius of Na ⁺ and K ⁺ in the particles, Li ⁺ in the glass of the present invention exhibit the accumulation effect, expansion coefficient of the glass is lowered.

  MgO is advantageous in reducing the expansion coefficient of glass and improving weather resistance. By adding a certain amount of MgO, it is effective for the glass transition temperature and the deflection temperature. However, if the content is too high, the devitrification resistance of the glass is rather deteriorated and the liquidus temperature is increased. Therefore, the content of MgO is limited to 2 to 10%, and a more preferable content is 4 to 8%.

  CaO improves the chemical stability of the glass and has a certain flux action. However, when the content exceeds 10%, the tendency of devitrification of the glass is increased. Therefore, the content of CaO is limited to 2 to 10%, and a more preferable content is 4 to 8%.

  ZnO is an optional component that reduces the tendency of glass to crystallize. However, its content should not be too high. Otherwise, the devitrification resistance and chemical stability of the glass are reduced and the scattering of the glass is increased. Therefore, the content of ZnO is limited to 0 to 3%, the more preferable content is 0 to 2%, and the most preferable is not to put.

  SrO is a component that adjusts the optical constant and improves the chemical stability of the glass. In the present invention, an appropriate amount can be added, but its content is 0 to 8%.

In the present invention, Sb ₂ O ₃ is used as a fining agent, and its content is 0 to 0.5%.

  In the following, the performance of the optical glass provided by the present invention will be described. Among them, the refractive index and the Abbe number are based on “GB / T 7962.1-1987 Colorless Optical Glass Measuring Method Refractive Index and Chromatic Dispersion Coefficient”.

  The transition temperature (Tg) is based on “GB / T796.26-1987 Colorless Optical Glass Measuring Method Linear Expansion Coefficient, Transition Temperature and Deflection Temperature”. That is, every time the sample to be measured rises by 1 ° C. within a certain temperature range, the sample to be measured is crossed by the extension line of the linear portion of the low temperature zone and the high temperature zone, and the intersection is the corresponding temperature. .

The measurement standard of water resistance is as follows.
Based on the following formula, the leaching percentage is calculated by the GB / T17129 measurement method.

D _W = (BC) / (BA) × 100%

In the formula:
D _W- Percentage of glass leaching (%);
B-Mass of filter and sample (g);
C-filter and mass of sample after erosion (g);
A-Filter mass (g).

The water resistance of the optical glass is classified into six categories according to the obtained percentage of leaching. Among them, the 1st class index is leaching percentage (D _W ) <0.04.

The acid resistance measurement standards are as follows.
Based on the following formula, the leaching percentage is calculated by the GB / T17129 measurement method.

D _A = (B−C) / (B−A) × 100%

In the formula:
D _A- Percentage of glass leaching (%);
B-Mass of filter and sample (g);
C-filter and mass of sample after erosion (g);
A-Filter mass (g).

The water resistance of the optical glass is classified into six categories according to the obtained percentage of leaching. Among them, the 4th class index is leaching percentage (D _A ) 0.65 to 1.20.

After the colorless optical glass is eroded by the atmosphere, an altered layer such as “atomization” occurs on the surface. The degree of erosion of the glass surface is determined by the turbidity difference before and after the sample erosion. For this reason, the glass is processed into dimensions of 30 mm × 30 mm × 10 mm specifications. Among them, two large surfaces are buffed, the surface roughness Ra is less than 0.025 μm, the shape accuracy N is 3 or less, the shape accuracy difference ΔN is less than 0.5, and the remaining surface is finish-polished. Clean with an ultrasonic cleaner or wipe the material using a mixed solvent of long fiber cotton, anhydrous alcohol which conforms to GB / T 678 standard and ether (1: 9) which conforms to GB / T 12591 standard. The turbidity H ₀ before the glass erosion is measured using a spectrophotometer, and then the sample for measurement is placed in an environment of saturated steam having a relative humidity of 90%, the temperature is raised to 40 ° C., and then 40 ° C. to 50 ° C. Then, the circulation is changed every hour, and after the test 30 h, the glass sample is taken out and the turbidity H ₁ after glass erosion is measured. The test distilled water is compatible with GB / T 6682 grade 2 distilled water.

  Turbidity difference calculation

ΔH = H ₁ −H ₀

In the formula:
ΔH-turbidity difference of eroded sample;
H ₁ --turbidity of the sample measured after erosion;
H _0- Turbidity of the sample measured before erosion.

  The turbidity ΔH and the weather resistance of the optical glass are classified into four categories. Among them, the class 1 index is a turbidity difference ΔH <0.3%.

  The glass is made as a sample with a thickness of 10 mm ± 0.1 mm, and when the projection ratio of the measurement glass reaches 80%, the corresponding wavelength is obtained.

By the test, the optical glass of the present invention has the following performance. When the refractive index (n _d ) of the optical glass is 1.60 to 1.65, the Abbe number is (υ _d ) 62 to 66, and the transmittance reaches 80%, the corresponding wavelength is lower than 370 nm, the transition temperature (Tg) does not exceed 550 ° C. Water resistant D _W One class, in acid resistance D _A 4 such a weatherproof One class. Accordingly, the optical glass is suitable for precision compression molding aspherical optical elements at low cost and high yield.

  The present invention further provides optical glass preforms and optical elements comprising methods familiar to those skilled in the art. Further, the optical preform and the optical element are used for a digital camera, a digital video camera, a camera phone, and the like.

  As means for solving the problems of the present invention, the precision compression-molded optical glass of the present invention will be described in more detail with reference to examples. However, the scope of rights of the present invention is not limited to these examples.

  Optical glass Examples 1 to 40 displayed in Tables 1 to 4 are ordinary raw materials for optical glass (for example, oxides, etc.) to be weighed and mixed based on the ratios of the individual embodiments shown in Tables 1 to 4. Hydrogen oxide, metaphosphate, carbonate, nitrate, etc.) Put mixed raw material into crucible, melt at constant temperature, further clarify, homogenize, and contain no bubbles and dissolved substances No homogeneous molten glass is obtained, and this molten glass is cast in a mold and annealed.

When the composition, refractive index (nd), Abbe number (vd), water resistance D _W , acid resistance D _A , weather resistance, transition temperature (Tg) and glass transmittance of Examples 1 to 40 of the present invention were 80% The wavelength λ80 is displayed in Tables 1 to 4. In these tables, the composition of individual compositions is expressed as a percentage by weight.

Examples of the above Table 1 to Table 4, the inventors have, by adjusting the blending ratio of each component reasonable, refractive index _(n d) _1.60~1.65 and the Abbe number (υ _d) 62 in -66, when the projection ratio reaches 80%, the wavelength of the correspondence below 370 nm, in acid resistance D _a 4 include, showed that weathering stability obtaining the optical glass 1 class. Therefore, it can be seen that the glass has excellent optical and physicochemical performance and is suitable for precision compression molding at low cost and high yield.

Claims (18)

The following ingredients in percentages by _{weight, P 2 O 5: 30~50%} , BaO: 39 ~50%, B 2 O 3: 2~ 4.5%, La 2 O 3: 0~5%, Gd 2 O 3 _{: 0~5%, Al 2 O 3} : 0.1~5%, Li 2 O: 0.1~5%, MgO: 2~10%, CaO: optical glass containing 2 to 10%. The optical glass according to claim 1, further comprising ZnO: 0 to 3%, SrO: 0 to 8%, and Sb ₂ O ₃ : 0 to 0.5%. Further _{P 2 O 5: 30~50%,} BaO: 39 ~50%, La 2 O 3: 0~5%, Gd 2 O 3: 0~5%, B 2 O 3: 2~ 4.5%, _{al 2 O 3: 0.1~5%,} Li 2 O: 0.1~5%, MgO: 2~10%, CaO: 2~10%, ZnO: 0~3%, SrO: 0~8% , _Sb 2 _O 3: optical glass according to claim 1 comprising 0 to 0.5%. The content of P ₂ O ₅ is 38 to 42%, the optical glass according to any one of claims 1 to 3.   The optical glass according to any one of claims 1 to 3, wherein the content of BaO is 39 to 45%. The content of B ₂ O ₃ is 2.5 to 4.5% optical glass according to any one of claims 1 to 3. The content of Al ₂ O ₃ is 1-5%, the optical glass according to any one of claims 1 to 3. Li ₂ O content is 1-3%, the optical glass according to any one of claims 1 to 3.   The optical glass according to any one of claims 1 to 3, wherein the MgO content is 4 to 8%.   The optical glass according to any one of claims 1 to 3, wherein the content of CaO is 4 to 8%. The content of Gd ₂ O content of ₃ 0 to 3% and / or _La 2 _{O 3} is 0-3%, the optical glass according to any one of claims 1 to 3. _{0.9 ≦ BaO / (P 2 O} 5 + B 2 O 3) is ≦ 1.5, the optical glass according to any one of claims 1 to 3. The optical glass according to claim 1, wherein 0.1% ≦ La ₂ O ₃ + Gd ₂ O ₃ ≦ 8%.   The optical glass according to any one of claims 1 to 13, wherein the optical glass has a refractive index of 1.60 to 1.65 and an Abbe number of 62 to 66. Less than 370nm wavelength corresponding to when the transmittance of the optical glass has reached 80%, in water resistance D _W of the optical glass is Class 1, in acid resistance D _A 4 include, in weather resistance class 1, transition temperature The optical glass according to any one of claims 1 to 13, which does not exceed 550 ° C.   The glass preform formed with the optical glass as described in any one of Claims 1-13.   The optical element formed with the optical glass as described in any one of Claims 1-13.   An optical device formed of the optical glass according to claim 1.